Electromagnetic (em) power density and field characterization technique

ABSTRACT

An apparatus and method for characterization of a directed beam of electromagnetic radiation is provided. An exemplary embodiment of the invention can include an apparatus and measuring technique method which uses a model for blackbody radiation that includes consideration all the degrees of freedom due to translation, vibration, and rotation of molecules or atoms that make up the absorber and a heat transfer term which averages the behavior of all the atoms of the material as a function of temperature. This apparatus and method provides an advantage of increased accuracy, substantial reductions of time required for processing, simplification of measuring processes, and reduction required equipment.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. patent application Ser. No.12/983,230, having a filing date of Dec. 31, 2010 which claims priorityto U.S. provisional patent application Ser. No. 61/362,823 having afiling date of Jul. 30, 2010, the disclosures of which are expresslyincorporated by reference herein.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

The invention described herein includes contributions by one or moreemployees of the Department of the Navy made in performance of officialduties and may be manufactured, used and licensed by or for the UnitedStates Government for any governmental purpose without payment of anyroyalties thereon.

BACKGROUND

The present invention relates to an apparatus, system and method forcharacterizing and measuring a directed electromagnetic (EM) fieldcharacterization, e.g., a radio frequency (RF) beam. Previous approachesto RF beam measurement employed a model of heat transfer from onemacroscopic body to another and blackbody radiation of a particle withonly one degree of freedom.

Other techniques can use a horn antenna, attenuators, and power meter tocollect data at different points along a plane perpendicular to thebeam. This technique is much more time consuming the apparatus is morecomplicated and in many cases must be automated with translationalstages in order to make an accurate measurement.

Additional features and advantages of the present invention will becomeapparent to those skilled in the art upon consideration of the followingdetailed description of the illustrative embodiment exemplifying thebest mode of carrying out the invention as presently perceived.

SUMMARY OF THE INVENTION

According to an illustrative embodiment of the present disclosure, anembodiment of the invention can be used to characterize a directed beamof EM radiation. In particular, an embodiment of the invention caninclude an apparatus and measuring technique method which uses a modelfor blackbody radiation which includes consideration of all the degreesof freedom due to translation, vibration, and rotation of molecules oratoms that make up the absorber and a heat transfer term which averagesthe behavior of all the atoms of the material as a function oftemperature. This apparatus and method provides an advantage ofincreased accuracy, substantial reductions of time required forprocessing, simplification of measuring processes, and reductionrequired equipment.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description of the drawings particularly refers to theaccompanying figures in which:

FIG. 1 shows a description of an exemplary system in accordance with oneembodiment of the invention.

FIG. 2 shows an exemplary functional description of software modulesdescribing one way of organizing processing sequences or software inaccordance with one embodiment of the invention.

FIG. 3 shows an exemplary graphical user interface for controllingprocessing, inputs, and producing outputs in accordance with oneembodiment of the invention.

FIG. 4 shows an exemplary description of data arrays used with softwareused for processing in accordance with one embodiment of the invention.

FIG. 5A shows an exemplary output associated with one type of EM sourceproduced and displayed in accordance with one embodiment of theinvention.

FIG. 5B shows an exemplary output associated with another type of EMsource produced and displayed in accordance with one embodiment of theinvention.

FIG. 6 shows an exemplary degrees of freedom table having data which isused in association with blackbody calculations for use in accordancewith one embodiment of the invention.

FIG. 7A shows an exemplary method used in producing outputs inaccordance with one embodiment of the invention.

FIG. 7B is a continuation of the FIG. 7A description of an exemplaryprocess in accordance with one embodiment of the invention.

FIG. 8 shows an exemplary data plot of temperature data versus framenumber of data collected from an EM source using one exemplaryembodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

The embodiments of the invention described herein are not intended to beexhaustive or to limit the invention to precise forms disclosed. Rather,the embodiments selected for description have been chosen to enable oneskilled in the art to practice the invention.

Referring to FIG. 1, an exemplary embodiment of an EM field measuringsystem is shown which includes an EM source 1 (e.g., an infraredsource), an EM absorption material 3 (e.g., a sheet of carbon loadedKapton®), and a temperature sensor array 5 (e.g., an infrared camera) tomeasure the temperature of the EM absorption material 3. The temperaturesensor array 5 is coupled with a processing system 7 which has software(further discussed below) for processing data received and outputtingdata representations characterizing an EM field which was directed onthe EM absorption material 3. These data representations can bedisplayed on a display system 9 or transmitted to a network via anetwork hub 11 for further processing, output, or other action. Softwareon the processing system 7 generally can be operable by a user via agraphical interface which permits interaction between the user andsystem via an interface system such as a keyboard 13 and a mouse 15however another interface can be used such as a touch screen (notpictured). Optionally, a gas or air circulation unit 17 can be used tokeep the EM absorption material 3 near or at room temperature for thepurposes of heat transfer from the absorber to ambient air or atmospheresurrounding the EM absorption material 3.

A variety of types of suitable coolant or temperature control system canbe used to provide a temperature control action/effect for the inventionparticularly where the system is in an environment where environmentalfactors or heat transfer variables can impact the overall resultsobtained by the temperature sensor array 5. In other words, temperaturesensor array data can be adversely impacted where environmental factorsalter the heat transfer characteristics of an EM absorption material 3e.g., being outside with variable winds, sun, etc which create changesin heat transfer from factors besides a particular EM source. Othertypes of heat transfer control components/systems can also be used,including multiple cooling mechanisms, heat sinks or other heat transferor control systems. Also, increased accuracy can be obtained by usingsuch a temperature control mechanism for an EM absorption material ingeneral, including indoor environments, as “hot pockets” or uneven heattransfer areas can form around the surface of a given EM absorptionmaterial preventing heat transfer to occur as convection forces alonefrequently are insufficient to ensure uniform heat transfer across theapplicable surface of a given EM absorption material.

Referring to FIG. 1, EM source 1 is energized and is positioned so an EMfield emitted by EM source 1 is incident onto the EM absorption material3. A temperature sensor array, e.g., an infrared (IR) camera framecapture, which shows the temperature of the absorption material, e.g.,Kapton®, before the EM source 1 is turned on, is used along with a frameof when the absorption material 3 has reached thermal equilibrium andthe time it took to reach thermal equilibrium. It should be noted thatanother embodiment can use another temperature sensor array for the EMAbsorber besides an IR camera such as an array of thermocouples whichcould produce simultaneous temperature readings of a region of interestof the EM absorber over a period of time. A variety of different EMabsorbers can be used with the invention as well.

Referring to FIG. 2, a functional diagram of processing softwareassociated with an exemplary embodiment of the invention is shown. An IRCamera Output Processing (IRCOP) Module 21 creates a Temperature Dataper Pixel (TDPP) array. IRCOP produces the TDPP array based on a seriesof IR camera image frame captures of an EM Absorber before, during, and,optionally, after exposure to an activated EM source (e.g., directedenergy beam or an EM field produced by an antenna or wave guide). Inparticular, the TDPP array stores a series of IR image frames orsnapshots of the EM absorber taken by the temperature sensor array 5(e.g., IR camera) over time. Each IR image frame comprises temperaturedata associated with pixels in the IR camera 5 used to capture each IRimage frame. The TDPP array includes a file name, a series of IR imageframe captures including a temperature data value for each pixel, andtime of capture for the temperature data value for each frame/pixel.This exemplary array can be stored as a compressed audio videointerleave (AVI) file.

A graphical user interface (GUI) Module 23 is provided for controllingoperations in the processing software and providing outputs. The GUIModule 23 creates GUIs such as are shown in FIG. 3.

A Temperature Differential Analysis (TDA) Module 25 includes a sectionfor determining an initial state temperature (e.g., a “cold” frame witha lowest overall temperature value) associated with one of the series ofIR image capture frames stored in the TDPP, a final state temperature(e.g., a “hot” frame associated with a highest overall temperaturevalue) associated with one of the series of IR image capture framesacquired over a period of time, and elapsed time between the initial andfinal state temperatures based on the TDPP array data. For example, theTDA Module 25 can select a “cold” IR image capture frame and a “hot” IRimage capture frame based on comparing all frames and finding the frameswhich have pixels which have lowest overall temperature and the highestoverall temperature. Processing in the TDA Module 25 can include datainput (e.g., TDPP array), pre-processing (e.g., determination of elapsedtime between initial and final states (e.g., “cold” and “hot” IR imagecapture frames), selection of an initial temperature state IR imagecapture frame (e.g. “cold”) and a final IR image capture frame (e.g.,“hot”)), calculation of differential temperature values per pixel, andtemperature differential (TD) array creation. In this example, theinitial temperature state is a state prior to EM source activation andfinal temperature state is a state where an EM Absorber 3 reaches apredetermined temperature such as an approximate peak temperature value.In an embodiment where a pulsed EM (e.g. RF) source is directed onto anEM absorber, the final temperature state can be at any point after theEM source is turned on where a maximum temperature value is reached oranother parameter (e.g., time) is met. An exemplary TD array includes anIR image capture frame determined to have the desired initialtemperature state (e.g., cold), an IR image capture frame determined tohave the desired final temperature state (e.g., “hot”), time valuesassociated with both selected IR image capture frames, and elapsed timeassociated with each selected IR image capture frame and/or pixels in anarray of temperature sensor array 5 e.g., IR Camera.

An exemplary Power Density Calculation (PDC) Module 27 calculates powerdensity associated with all or selected pixels in the selected IR imagecapture frames (i.e., “cold” and “hot” frames) from a temperature sensorarray 5 (e.g., IR Camera) and stores it in a Power Density per Pixel(PDPP) array. The PDC Module 27 receives inputs including inputs fromthe TDA Module 25 including the TD array 47. Power density in thisexample is calculated based on at least two temperature sensor arraycaptures selected using temperature data values (e.g., initial IR imagecapture frame (e.g., “cold) and final IR image capture frame (e.g.,“hot”)), elapsed time between at least two temperature sensor arraycaptures, reflection and transmission coefficients of an EM absorber,degrees of freedom data associated with atoms in the EM absorber (e.g.,see FIG. 6 table), emissivity of the EM absorber, Stefan-Boltzmann'sConstant, specific heat capacity of the EM absorber, density of a mediumwhich is used to cool the EM absorber (e.g., air, heat sink, etc),volume of medium used to cool the EM absorber, and area of interfacebetween the medium used to cool the EM absorber and the EM absorber. Analternate embodiment can include an EM absorber which is sufficientlylarge enough to act as a heat sink for itself and thereby add to themedium used to cool the EM absorber therefore must be factored into theprocessing by the PDC Module 27. A general form of a power densitycalculation performed by the PDC Module 27 is provided in FIG. 7A. Powerdensity calculation performed in this exemplary PDC Module 27 can beaffected by selection of different EM absorbers and various factorsincluding cooling of the EM absorber.

An example of processing performed in PDC Module 27 for a specific EMabsorber can include a thermal imaging and millimeter wave measurementtechnique using a carbon loaded polymer sheet called Kapton® andtreating it as a diatomic gas. An exemplary calculation for a particularEM absorber, a Kapton® EM absorber, and the exemplary testingconfiguration shown in FIG. 1, and the software described in FIG. 2 isshown in Equation 1.

$\begin{matrix}{P = {\frac{2}{1 - {\Gamma }^{2} - {\tau }^{2}}\left\lbrack {{2ɛ_{ir}{\sigma_{b}\left( {T_{s}^{4} - T_{0}^{4}} \right)}} + {\frac{C\; \rho_{K}}{\Delta \; t}\left( {T_{s} - T_{0}} \right)}} \right\rbrack}} & (1)\end{matrix}$

where, τ=Coefficient of transmission, Γ=Coefficient of reflection,σ_(b)=Stefan-Boltzmann constant (W/cm²-K⁴), ε_(ir)=emissivity ofKapton®, T_(s)=Temperature of sample (Kelvin), T₀=Initial temperature ofsample (Kelvin), Δt=Time to equilibrium (seconds), ρ_(K)=Density ofKapton® (kg/cm²), and C=Specific Heat (J/g-K). Note that the portion ofequation 1 which has the coefficient of transmission and coefficient ofreflection outside the brackets is an absorption coefficient, in thiscase for the EM material. A power density formula, such as shown inequation 1, must be adapted to a particular material composition used inthe EM absorber. An exemplary Data Output Processing (DOP) Module 29provides various outputs including a power density image (PDI) array.The PDI array stores data required to produce a digital representationthat is displayed in cooperation with the GUI Module 23 and furtherdiscussed in connection with FIG. 4.

The Data Array 30 section of this exemplary embodiment stores dataassociated with processing in an exemplary embodiment of the system.Data arrays in this embodiment include TDPP produced by IRCOP Module 21,TD array produced by the TDA Module 25, a PDPP array produced by the PDCModule 27, and PDI array associated with DOP Module 29. A ConfigurationData Array (CDA) can be provided to store data which is used inprocessing such as the degrees of freedom data. It should be noted thata variety of data structures can be used to perform the function of DataArray 30. For example, data arrays can be local to code modules orglobal data arrays.

Referring to FIG. 3, a screen view of a main control graphical userinterface 31 is shown associated with processing software. A processcontrol 33 is used to commence execution of the processing system 7.After the process control 33 is selected, a file path input dialogwindow (not shown) is displayed to permit selection of a file pathsimilar to Windows Explorer for use in navigating file structures andselecting a file stored on a computer system running the software. Adialog (or dialogue) box is a special window, used in user interfaces todisplay information to the user, or to get a response if needed. Theyare so-called because they form a dialog between the computer and theuser—either informing the user of something, or requesting input fromthe user, or both. It provides controls that allow a user to specify howto carry out an action. A display field 35 is provided to show the filepath information selected using the file path input dialog window (notshown). A Mode Selector 41 dialog box permits a user to select anautomatic or manual process for identifying an initial IR image captureframe (e.g., “cold” frame) data and final IR image capture frame (e.g.,“hot” frame) data associated with a series of IR image capturesoutputted by a temperature sensor array (e.g., IR camera) and stored ina data array.

Referring to FIG. 4, another organization of the data arrays describedin association with the Data Arrays Module of FIG. 2 is provided. Inthis example, the data arrays are shown in separate format from the FIG.2 representation but with the same functionality and purpose to includethe TDPP Array 45, TD Array 47, TDPP Array 49, PDPP Array 51, PDI Array53, and CDA Array 55.

Referring to FIG. 5A, an exemplary power density image output 59associated with Gaussian Optical Lens Antenna (GOLA) antenna produced bythe GUI Module 23 is shown. This power density image output 59 can beproduced based on data including PDI array data generated by DOP Module29. This power density image output 59 can be displayed in the imageviewer window 37 (FIG. 3). The power density image output 59 in thisembodiment is a graphical image showing power density per pixel of an IRCamera (e.g., 5) produced using embodiment of the invention.

The power density image output 59 in this embodiment includes agraphical representation of an EM field produced by an EM source undertest where the representation is made up of different colors associatedwith different ranges of power density values. This output shows one wayto represent power density per pixel by characterizing an EM source(e.g., an antenna field pattern) plus pattern density in onerepresentation. Each pixel in this output has a power density dataassociated with that pixel. In this example, different colors are usedfor a number of ranges of power density such as red for a peak range andblue for the lowest data range. These ranges are predetermined, selectedin advance, and associated with a particular color representation inthis embodiment. The output processing software associated a desiredcolor with a given power density data value associated with a particularpixel by determining which range the power density data value fallswithin.

For example, in FIG. 5A a series of differently colored regions is shownwhich are roughly surrounding a maximum EM field incident on an EMabsorber under test. In particular, in this exemplary representation abackground (blue) region 61 represents no EM field incident on the EMabsorber. A light blue or hazy area 65 within the background regionrepresents the weakest measured range of EM field(s) incident on the EMabsorber. A green region 63 which is within the white or hazy region 65represents the next higher range of power density measured associatedwith the EM field incident on the EM absorber under test. A yellowregion 67 which is within the green region 63 represents the next higherrange of power density measured associated with the EM field incident onthe EM absorber under test. A red region 69 which is within the yellowregion 67 represents the highest power density measured associated withthe EM field incident on the EM absorber under test.

This power density image output 59 permits characterization of an EMfield produced by an EM source under test. The exemplary power densityimage output 59 also provides an ability to display a specific powerdensity value 39 (FIG. 3) for a specific pixel. One embodiment of theinvention can include provision of a pointing device or anelectronically manipulated cursor which can be moved over each pixel inthe power density image output 59. A power density per pixel data value39 (FIG. 3) will appear when the pointing device or cursor points toeach pixel. One embodiment of the invention can include a provision fordisplaying a power density maximum data value (Pmax 43, FIG. 3) thatwill appear showing a highest power density data value 43 for a specificpixel contained in the exemplary power density image output 59.

Outputs (e.g., power density image output 59) from the DOP 29 and GUIModule 23 can be used to determine field strength of an EM source in aspecific area of space, near field analysis, or far field analysis.Other modeling and analysis outputs can be produced with this inventionbased on representation of EM fields associated with an EM sourcegenerating a field into free space. One example is producing arepresentation and analysis of 3 db spot sizes of a directed energy beamor an antenna.

FIG. 5B shows a different representation of an EM field produced by aW-band pyramidal standard gain antenna coupled to an EM source undertest using an embodiment of the invention. In this example, the sametype of power density color representation scheme is used as is shown inFIG. 5A, however the distribution of the power density/colors aredifferent due to the differences in EM field(s) measured using anembodiment of the invention.

Any number of or variety of antennas can be used with the invention.Other EM sources/antennas/coupling devices which can be used with theinvention include waveguides, lasers, or any other EM spectrum sourcewhich produces a change, e.g., a temperature change, in the EM absorber.

FIG. 6 shows an exemplary degrees of freedom table having data which isused in association with blackbody calculations. In particular, thistable can be used for computing the number of degrees of freedom of asystem of atoms or molecules which comprise an EM absorber where n isthe number of atoms per molecule, e.g., a sheet of carbon loadedKapton®. The table includes position, rotation, and vibration formonatomic atoms as well as linear and non-linear molecules. These valuesare predetermined and used to obtain one factor of the co-efficient of ablackbody radiation term used in calculations associated with anembodiment of the invention. In this example, the FIG. 5 table is usedin processing which is performed by the PDC Module 27. The degrees offreedom table can include degrees of information data associated withdifferent types of materials used as EM absorbers. For example, in theexemplary table in FIG. 6 different ways to calculate or representdegrees of freedom for different materials is shown. For Kapton®, thereis a carbon powder pressed into a polymer sheet. Because the carbon isin powder form, it has three degrees of freedom of position and 3n−5degrees of freedom in vibration plus 3 in position which gives 3n−2.Based on this position and vibration information, total degrees offreedom for Kapton® is then 4 (i.e., 3n−2 where n=2 given carbon is adiatomic atom with 2 atoms per molecule) for the powder form of carbon.Different table values and potentially different table compositions ordata elements may be required for different embodiments of the inventionincluding different EM absorbers.

FIGS. 7A and 7B shows steps used in producing outputs in accordance withone embodiment of the invention. In step 1 (73), provide an EM source(e.g., an RF source). In step 2 (75), provide an EM absorber. In step 3(77), provide an array of temperature sensors (e.g., an infraredcamera). In step 4 (79), provide a temperature control mechanism (e.g.,circulation fan) (optional). In step 5 (81), provide a processingsystem, network and input/output system. In step 6 (83), position thearray of temperature sensors and the EM source to orient on the EMabsorber based on a desired measurement of an EM field produced by theEM source. In step 7 (85), capture a series of temperature image dataframes (e.g., infrared image frame captures) and saving each temperatureimage data frames that includes temperature per pixel data and timeassociated with each temperature image data frame to a Temperature Dataper Pixel (TDPP) data array. In step 8 (87), start processing software.In step 9 (89), initialize system and input data from TDPP Array. Instep 10 (91), select an initial temperature image data frame (e.g.,coldest/ambient temperature or time prior to activation of EM source)and a final temperature image data frame (e.g., hot or highesttemperature) from the series of temperature image data frames and storein a power density per pixel array (PDPP) array. In step 11 (93),calculate power density associated with each pixel in the initial andfinal frames selected at step 10 (91) based on determining a pluralityof characteristics of an EM absorber including absorption coefficient ofthe EM absorber, degrees of freedom for atoms or molecules associatedwith the EM absorber, emissivity, Stefan-Boltzmann's Constant, number ofsides being cooled, specific heat capacity of coolant, density ofcoolant, volume of coolant, area that the coolant will be in contactwith EM absorber, change in time between initial and final framecapture, and an initial and final temperature data of the EM absorber.Equation 2 provides an exemplary power density calculation formula thatcan be used in step 11 (93).

$\begin{matrix}{\frac{1}{1 - \tau - \Gamma}\left\lbrack {{D\; ɛ\; {\sigma_{b}\left( {T^{4} - T_{0}^{4}} \right)}} + \underset{{All}\mspace{14mu} {Heat}\mspace{14mu} {Sinks}}{\sum\; {\frac{C\; \rho \; V}{\Delta \; t\; A}\left( {T - T_{0}} \right)}}} \right\rbrack} & (2)\end{matrix}$

Where Γ is the coefficient of absorption of the EM absorber, τ is thecoefficient of transmission of the EM absorber, T is the finaltemperature of the EM absorber, T₀ is the initial temperature of the EMabsorber, ε is the emissivity of the EM absorber, σ_(b) is theStefan-Boltzmann constant, C is the specific heat of the heat sink(coolant), V is the volume of the heat sink (coolant), ρ is the densityof the heat sink (coolant), A is the contact area between the absorberand the heat sink (coolant), Δt is the time between the initial frame tothe final frame, and D is the degrees of freedom of the atoms ormolecules that comprise the EM absorber. In step 12 (95), produce outputof an image representation of power density of EM field calculated forevery pixel in the selected IR image capture frames (e.g., “cold” and“hot”).

An alternate embodiment of a power density measurement method inaccordance with the invention for pulsed power density measurement couldinclude steps 1 (73) through step 10 (91). The alternate embodimentprocessing for alternate embodiment step 11 would then deviate using analternate power density calculation using the formula described inequation 3.

$\begin{matrix}{\sum\limits_{l = 0}^{L}\; {\frac{1}{1 - \tau - \Gamma}\left\lbrack {{4D\; ɛ\; \sigma_{b}{T_{l}^{3}\left( {T_{l} - T_{l - 1}} \right)}} + {\sum\; {\underset{{All}\mspace{14mu} {Heat}\mspace{14mu} {Sinks}}{\frac{C\; \rho \; V}{\left( {t_{l} - t_{l - 1}} \right)A}}\left( {T_{l} - T_{l - 1}} \right)}}} \right\rbrack}} & (3)\end{matrix}$

Regarding equation 3, the first summation is a sum over data pointsmeasuring the temperature of the absorber. L is the total number oftemperature data frames being sampled and summed. l is a variable ofsummation in equation 3 representing the lth temperature data frame orthe variable which is being summed. The second summation is over allheat sinks in contact with the absorber. Γ is the coefficient ofabsorption of the EM absorber, T is the coefficient of transmission ofthe EM absorber, T_(l) is the final temperature of the EM absorber ofthe lth frame, T_(l-1) is the initial temperature of the EM absorber ofthe l−1 frame, ε is the emissivity of the EM absorber, σ_(t), is theStefan-Boltzmann constant, C is the specific heat of the heat sink(coolant), V is the volume of the heat sink (coolant), ρ is the densityof the heat sink (coolant), A is the contact area between the absorberand the heat sink (coolant), Δt is the time between the initial frame(t_(l-1)) to the final frame (t_(l)), D is the degrees of freedom of theatoms or molecules that comprise the EM absorber. In the pulsed poweralternative embodiment, a modified step 10 would include a selection ofadditional said temperature image data frames in between said initialand final temperature image data frames and determines associated timedifferentials between consecutive said selected additional temperatureimage data frames. As described above, a modified step 11 furtherserially calculates power density between each two of each selectedtemperature image data frames then said processing continues by summingall of the power density data for each two consecutive temperature imagedata frame from the initial frame to the final frame to produce a finalpower density data. For pulsed power density calculations, when summingthe power density of all power density computations, the final solutionis calculated by dividing by the total number of paired frames minusone. For example, where six frames are used to compute power density forpulsed power, the sum of the power density values must be divided byfive (i.e., 6 total frames −1).

Next, at step 12, an output would be generated showing an image of an EMfield associated with the EM source based on power density calculatedfor every pixel in an initial or “cold” IR image capture frame and afinal or “hot” IR image capture frame.

In this pulsed power alternate embodiment of a power density measurementmethod, it is possible to make a pulsed power density measurement usingas few as two data points which show the temperature rise from initialtemperature to final temperature instead of waiting for the temperatureto reach equilibrium.

FIG. 8 shows an exemplary data plot of temperature data versus framenumber of data collected from an EM source using one exemplaryembodiment of the invention. A processing system in accordance with anembodiment of the invention sequentially analyzes each IR image captureframe starting a selected time e.g., t=0, then looks for the highesttemperature reading associated with all the pixels in each frame, thenplots the temperature value for each frame. Each data plot on this tableshows a maximum temperature value for each separate IR image framecapture. The x-values in this table represent an individual IR imageframe. In other words, each temperature data on the y-axis represents apixel having the highest temperature in a frame capture comprising anynumber of pixels which were sampled during a given integration time perframe capture using an EM sensor, in this example an IR camera. The plotbegins with a series of temperature data readings associated with aseries of IR image capture frames before an EM source is energized andoriented on an EM absorber. After the EM source is energized, then atemperature data is plotted sequentially for each IR image capture frameon the x axis until the system reaches the end of the IR image captureframes.

An alternative embodiment of the invention can further include amechanism adapted to move the EM source and/or the EM absorber relationto each other in order to manipulate either the EM field which is beingmeasured or manipulate the EM absorber to move it through the EM fieldwhich is being measured. An additional set of components and softwarewould be used to track the position of the EM field and/or the EMabsorber and associate positional and time information with eachmovement of the EM absorber and/or EM source. These additionalcomponents, in addition to the components described above, would be usedto collect sufficient data required to compute the power density andother characteristics associated which each plane of the EM field whichthe EM absorber was placed within. A series of software instructions forcontrolling the movement of the EM absorber and/or the EM source andthen collecting separate data or measurements for each position of theEM source and/or EM absorber would be incorporated into the aboveembodiments of the invention. The output would then be a series of planeimages of the EM field under test or a three dimensional image of the EMfield under test which could include a three dimensional power densityrepresentation using the same or a different color scheme as describedabove. An output system could use a pointer system or a plane whichcould then be used to select specific cross sections of the threedimensional field.

Another embodiment could include manipulating the EM absorber andtemperature sensor array around an area where the EM field is largerthan the EM absorber. In this embodiment, the temperature sensor arrayand EM absorber would be positioned to take a number of sequentialmeasurements which would be individually processed, then compiled into amosaic to describe the overall area of interest where the EM field ofinterest is located.

Another embodiment can include changing the distance between the EMabsorber and the EM source in order to take different measurements whichwould then be used to determine phase and amplitude characteristics ofthe EM source.

Another alternative embodiment can be used to characterize an EMabsorber where the EM source and the temperature sensor array arecalibrated and performance characteristics are known. This embodimentcan be then be used to analyze physical characteristics of the EMabsorber. An example could be determining a sample characteristics basedon comparisons with known values such as specific heat capacity, densityof material, atomic makeup of the material under test.

Another alternative embodiment of the invention could be used tocharacterize EM absorption of an atmosphere. The system would beoriented on an atmosphere where a star would be used as the EM source.An initial frame would be when the star is not oriented on atmosphere ofthe planet of interest (e.g., on its cold side), then take anotherseries of frame captures when the star is oriented on the atmosphere ofinterest.

Benefits of the invention include being able to make parallelmeasurements versus serial or piece-meal measurements. Also, theinvention permits high resolution measurements with significantly lesseffort, equipment, time and resources than currently required to producedesired outputs.

Although the invention has been described in detail with reference tocertain preferred embodiments, variations and modifications exist withinthe spirit and scope of the invention as described and defined in thefollowing claims.

1. An electromagnetic field characterization apparatus comprising: anelectromagnetic source adapted to emit an electromagnetic field; anelectromagnetic absorption material adapted to receive saidelectromagnetic field; a plurality of temperature sensors adapted toorient on said electromagnetic absorption material and output aplurality of temperature sensor data; a plurality of processingsequences comprising: a first processing sequence adapted to receivesaid plurality of temperature sensor data and store a plurality oftemperature sensor data frames created based on said plurality oftemperature sensor data in a first data structure, said temperaturesensor data frames comprise a plurality of temperature data associatedwith some or all of said temperature sensors stored at different pointsof time; a second processing sequence adapted to select at least two ofsaid temperature sensor data frames based at least on a first and secondtemperature data parameter determined based on comparisons of all saidtemperature sensor data frames to find an initial state and a finalstate associated with temperature changes in said electromagneticabsorption material, said at least two selected temperature sensor dataframes comprise an initial and final temperature sensor data frame, saidsecond processing sequence is further adapted to determine a timedifferential data for every two of said selected at least twotemperature sensor data frames, said second processing sequence isfurther adapted to store said selected at least two temperature sensordata frames and said time differential data in a second data structure;a third processing sequence adapted to determine a plurality of powerdensity data associated with some or all of said plurality oftemperature data in said initial and final temperature sensor dataframes, said plurality of power density data is determined based on datastored in said second data structure, absorption attributes associatedwith said electromagnetic absorption material, a plurality of blackbodyradiation attributes associated with said electromagnetic absorptionmaterial comprising degrees of freedom attributes, and a plurality ofcooling attributes associated with a cooling medium in proximity to saidelectromagnetic absorption material, said second processing sequencefurther outputs and stores a power density image map in a third datastructure, said power density image map comprising a power density dataassociated with all or a portion of said plurality of temperaturesensors; and a fourth processing sequence adapted to produce a graphicalor data output of said power density image map.
 2. An electromagneticfield characterization apparatus as in claim 1, further comprisingproviding a temperature control mechanism which provides cooling to saidelectromagnetic absorption material.
 3. An electromagnetic fieldcharacterization apparatus as in claim 2, wherein said temperaturecontrol mechanism is a circulation fan adapted to ensure approximatelyuniform heat transfer associated with said electromagnetic absorptionmaterial;
 4. An electromagnetic field characterization apparatus as inclaim 1, wherein said electromagnetic source is a radio frequency sourcecoupled to an electromagnetic field radiating structure.
 5. Anelectromagnetic field characterization apparatus as in claim 1, whereinsaid plurality of temperature sensors comprises one or more infraredimage sensing systems.
 6. An electromagnetic field characterizationapparatus as in claim 1, wherein said first and second temperature dataparameters are determined based on a determination of a high and lowtemperature value associated with a first and second approximatetemperature equilibrium defined as a case where temperature change inthe electromagnetic absorption material does not exceed a predeterminedvalue over a predetermined period of time.
 7. An electromagnetic fieldcharacterization apparatus as in claim 1, wherein said first temperatureparameter is a lowest temperature data value and said second temperatureparameter is a highest temperature value.
 8. An electromagnetic fieldcharacterization apparatus as in claim 1, further comprising a mechanismadapted to move said electromagnetic source or the electromagneticabsorption material in relation to each other in order to manipulateeither said electromagnetic field which is being measured or manipulatethe electromagnetic absorption material to move it through theelectromagnetic field which is being measured in order to produce aplurality of power density image maps each representing a differentplane measurement of said electromagnetic field or a three-dimensionalpower density image map.
 9. An electromagnetic field characterizationapparatus as in claim 1, wherein said first processing sequence furtherselects additional said temperature sensor data frames in between saidinitial and final temperature sensor data frames and determinesassociated time differentials between consecutive said selectedadditional temperature sensor data frames, wherein said secondprocessing sequence for calculating a power density data furtherserially calculates power density between each two of said selectedtemperature sensor data frames then said second processing sequence sumsall of the power density data for each two consecutive temperaturesensor data frame from said initial frame to said final frame to producea final power density data.
 10. An electromagnetic fieldcharacterization apparatus comprising: an electromagnetic source adaptedto emit electromagnetic field; an electromagnetic absorption materialadapted to receive said electromagnetic field; a plurality oftemperature sensors adapted to orient on said electromagnetic absorptionmaterial and output a plurality of temperature sensor data frames data,wherein said plurality of temperature sensors comprise a plurality oftemperature sensor pixels and said plurality of temperature sensor dataframe data each store a temperature data output from each saidtemperature sensor pixels; a plurality of processing sequencescomprising: a first processing sequence adapted to select and store aninitial and final temperature sensor data frame from said plurality oftemperature sensor data frames based on a first and second temperatureparameter, said first processing sequence further determines adifferential temperature data associated with said initial and finaltemperature sensor data frames; a second processing sequence forcalculating a power density data associated with all or a portion ofsaid plurality of temperature sensors and said final temperature sensordata frame, said second processing sequence determines said powerdensity data based on a power density per said pixel calculationcomprising a peak power density value based on a plurality ofcalculation elements comprising a coefficient of absorption of theelectromagnetic absorption material, a coefficient of transmission ofthe electromagnetic absorption material, the final temperature of theelectromagnetic absorption material, the initial temperature of theelectromagnetic absorption material, emissivity of the electromagneticabsorption material, Stefan-Boltzmann constant, a specific heat of atleast one heat sink, a volume of the at least one heat sink, a densityof the at least one heat sink, a contact area between theelectromagnetic absorption material and the at least one heat sink, atime differential between the initial and final temperature sensor dataframes, and degrees of freedom of atoms or molecules that comprise theelectromagnetic absorption material and a plurality of inputs to saidpower density per said pixel calculation including said differentialtemperature data, wherein said calculation is modified based on aparticular said electromagnetic absorption material, wherein themodified calculation components are coefficient of absorption of theelectromagnetic absorption material, a plurality of degrees of freedomdata for atoms or molecules associated with said electromagneticabsorption material, emissivity of blackbody radiation associated withsaid electromagnetic absorption material, specific heat capacity of theat least one heat sink placed in proximity to said electromagneticabsorption material, density of the at least one heat sink, volume ofthe at least one heat sink, and area of interface between the at leastone heat sink and said electromagnetic absorption material; and a thirdprocessing sequence for producing at least one graphical user interface,said at least one graphical user interface comprises a power densityimage output produced based on a plurality of ranges of power densityvalues which depicts said power density data, said at least onegraphical user interface also is adapted to display one or more saidpower density data associated with at least one of said plurality oftemperature sensors.
 11. An electromagnetic field characterizationapparatus as in claim 10, further comprising a processing system adaptedto process said plurality of processing sequences and produce aplurality of outputs comprising said power density image output.
 12. Anelectromagnetic field characterization apparatus as in claim 10, furthercomprising providing a temperature control mechanism which providescooling to said electromagnetic absorption material.
 13. Anelectromagnetic field characterization apparatus as in claim 12, whereinsaid temperature control mechanism is a circulation fan.
 14. Anelectromagnetic field characterization apparatus as in claim 10, whereinsaid electromagnetic source is a radio frequency source coupled to anelectromagnetic field radiating structure.
 15. An electromagnetic fieldcharacterization apparatus as in claim 10, wherein said plurality oftemperature sensors comprises one or more infrared image sensingapparatus.
 16. An electromagnetic field characterization apparatus as inclaim 10, wherein said plurality of temperature sensors is a videocamera adapted to record infrared or near infrared spectrum energy. 17.An electromagnetic field characterization apparatus as in claim 10,wherein said first temperature parameter is a lowest temperature datavalue and said second temperature parameter is a highest temperaturevalue.
 18. An electromagnetic field characterization apparatus as inclaim 10, further comprising a mechanism adapted to move saidelectromagnetic source or the electromagnetic absorption materialrelation to each other in order to manipulate either saidelectromagnetic field which is being measured or manipulate theelectromagnetic absorption material to move it through theelectromagnetic field which is being measured.
 19. An electromagneticfield characterization apparatus as in claim 10, wherein said firstprocessing sequence further selects additional temperature sensor dataframes in between said initial and final temperature sensor data framesand determines associated time differentials between consecutive saidadditional temperature sensor data frames, wherein said secondprocessing sequence for calculating a power density data furtherserially calculates power density between each two selected temperaturesensor data frames then said second processing sequence sums all of thepower density data for each two consecutive temperature sensor dataframe from said initial frame to said final frame to produce a finalpower density data.
 20. An electromagnetic field characterizationapparatus comprising: an electromagnetic source adapted to produceelectromagnetic radiation; an electromagnetic absorption materialadapted and positioned to said electromagnetic radiation; at least onearray of temperature sensors adapted to focus on said electromagneticabsorption material and output a plurality of temperature sensor dataframes comprising a plurality of temperature sensor data associated witha single temperature sensor in said array, wherein each said temperaturesensor data frame is associated with a different time data value thanother said temperature sensor data frames; a plurality of processingsequences comprising: a first processing sequence adapted to store saidplurality of temperature sensor data frames and store said plurality oftemperature sensor data frames in a first data structure; a secondprocessing sequence adapted to analyze data stored in said first datastructure and select an initial temperature sensor data frame and afinal temperature sensor data frame, wherein said initial and finaltemperature sensor data frames are selected from said plurality ofsensor data frames stored in said first data structure based ondetermination of an initial and final temperature data associated withat least two of said plurality of temperature sensor data frames, saidsecond processing sequence further determines a differential time dataassociated with said initial and final temperature data frames based ona first and second temperature parameter, said second processingsequence further stores said initial and final temperature sensor dataframes and said differential time data a second data structure; a thirdprocessing sequence comprises a power density per temperature sensorcalculation adapted to calculate a plurality of power density dataassociated with said final temperature sensor data frames and said timedifferential data stored in said second data structure, said thirdprocessing sequence is further adapted to store said plurality of powerdensity data in a third data structure, each power density data isindividually associated with one or more temperature sensors in said atleast one array of temperature sensors, wherein said plurality of powerdensity data is calculated based on: a blackbody radiation calculationbased on said electromagnetic radiation associated with said initial andfinal temperature sensor data frames; a determination of cooling of saidelectromagnetic absorption material based on said initial and finaltemperature sensor data frames and said differential time data; acoefficient of a blackbody radiation term determined based on at least aplurality of degrees of freedom data each associated with at least onecategory of atoms or molecules making up said electromagnetic absorptionmaterial; a plurality of constants associated with said electromagneticabsorption material comprising emissivity, Stefan-Boltzmann Constant,specific heat capacity of a cooling medium placed in proximity to saidelectromagnetic absorption material, density of said cooling medium,volume of said cooling medium, and an area that said cooling mediummakes contact with said electromagnetic absorption material; and a datavalue determined based on how much of said electromagnetic radiationincident on said electromagnetic absorption material is absorbed by saidelectromagnetic absorption material; a fourth processing sequenceadapted to produce a plurality of outputs comprising a power densityimage representation based on said plurality of power density data. 21.An electromagnetic field characterization apparatus as in claim 20,further comprising a processing system adapted to process said pluralityof processing sequences and data structures and produce a plurality ofsaid outputs comprising said power density image representation.
 22. Anelectromagnetic field characterization apparatus as in claim 20, whereinsaid second processing sequence further selects additional temperaturesensor data frames in between said initial and final temperature sensordata frames and determines associated time differentials betweenconsecutive said additional temperature sensor data frames, wherein saidthird processing sequence for calculating a power density pertemperature sensor data further serially calculates power densitybetween each two selected temperature sensor data frames then saidsecond processing sequence sums all of the power density data for eachtwo consecutive temperature sensor data frames from said initial frameto said final frame to produce a final said plurality of power densitydata.
 23. An electromagnetic field characterization apparatus as inclaim 20, further comprising providing a temperature control mechanismwhich provides cooling to said electromagnetic absorption material. 24.An electromagnetic field characterization apparatus as in claim 20,wherein said temperature control mechanism is a circulation fan.
 25. Anelectromagnetic field characterization apparatus as in claim 20, whereinsaid electromagnetic source is a radio frequency source coupled to anelectromagnetic field radiating structure.
 26. An electromagnetic fieldcharacterization apparatus as in claim 20, wherein said plurality oftemperature sensors comprises one or more infrared image sensingapparatus.
 27. An electromagnetic field characterization apparatus as inclaim 20, wherein said first temperature parameter is a lowesttemperature data value and said second temperature parameter is ahighest temperature value.
 28. An electromagnetic field characterizationapparatus as in claim 20, further comprising a mechanism adapted to movesaid electromagnetic source or the electromagnetic absorption materialrelation to each other in order to manipulate either saidelectromagnetic field which is being measured or manipulate theelectromagnetic absorption material to move it through theelectromagnetic field which is being measured.
 29. A method ofmanufacturing an electromagnetic field characterization apparatuscomprising: providing an electromagnetic source adapted to emit anelectromagnetic field; providing an electromagnetic absorption materialadapted to receive said electromagnetic field; providing a plurality oftemperature sensors adapted to orient on said electromagnetic absorptionmaterial and output a plurality of temperature sensor data; providing aplurality of processing sequences comprising: a first processingsequence adapted to receive said plurality of temperature sensor dataand store a plurality of temperature sensor data frames created based onsaid plurality of temperature sensor data in a first data structure,said temperature sensor data frames comprise a plurality of temperaturedata associated with some or all of said temperature sensors stored atdifferent points of time; a second processing sequence adapted to selectat least two of said temperature sensor data frames based at least on afirst and second temperature data parameter determined based oncomparisons of all said temperature sensor data frames to find aninitial state and a final state associated with temperature changes insaid electromagnetic absorption material, said at least two selectedtemperature sensor data frames comprise an initial and final temperaturesensor data frame, said second processing sequence is further adapted todetermine a time differential data for every two of said selected atleast two temperature sensor data frames, said second processingsequence is further adapted to store said selected at least twotemperature sensor data frames and said time differential data in asecond data structure; a third processing sequence adapted to determinea plurality of power density data associated with some or all of saidplurality of temperature data in said initial and final temperaturesensor data frames, said plurality of power density data is determinedbased on data stored in said second data structure, absorptionattributes associated with said electromagnetic absorption material, aplurality of blackbody radiation attributes associated with saidelectromagnetic absorption material comprising degrees of freedomattributes, and a plurality of cooling attributes associated with acooling medium in proximity to said electromagnetic absorption material,said second processing sequence further outputs and stores a powerdensity image map in a third data structure, said power density imagemap comprising a power density data associated with all or a portion ofsaid plurality of temperature sensors; and a fourth processing sequenceadapted to produce a graphical or data output of said power densityimage map.
 30. A method of manufacturing an electromagnetic fieldcharacterization apparatus as in claim 29, further comprising providinga temperature control mechanism which provides cooling to saidelectromagnetic absorption material.
 31. A method of manufacturing anelectromagnetic field characterization apparatus as in claim 30, whereinsaid temperature control mechanism is a circulation fan adapted toensure approximately uniform heat transfer associated with saidelectromagnetic absorption material;
 32. A method of manufacturing anelectromagnetic field characterization apparatus as in claim 29, whereinsaid electromagnetic source is a radio frequency source coupled to anelectromagnetic field radiating structure.
 33. A method of manufacturingan electromagnetic field characterization apparatus as in claim 29,wherein said plurality of temperature sensors comprises one or moreinfrared image sensing systems.
 34. A method of manufacturing anelectromagnetic field characterization apparatus as in claim 29, whereinsaid first and second temperature data parameters are determined basedon a determination of a high and low temperature value associated with afirst and second approximate temperature equilibrium defined as a casewhere temperature change in the electromagnetic absorption material doesnot exceed a predetermined value over a predetermined period of time.35. A method of manufacturing an electromagnetic field characterizationapparatus as in claim 29, wherein said first temperature parameter is alowest temperature data value and said second temperature parameter is ahighest temperature value.
 36. A method of manufacturing anelectromagnetic field characterization apparatus as in claim 29, furthercomprising a mechanism adapted to move said electromagnetic source orthe electromagnetic absorption material in relation to each other inorder to manipulate either said electromagnetic field which is beingmeasured or manipulate the electromagnetic absorption material to moveit through the electromagnetic field which is being measured in order toproduce a plurality of power density image maps each representing adifferent plane measurement of said electromagnetic field or athree-dimensional power density image map.
 37. A method of manufacturingan electromagnetic field characterization apparatus as in claim 29,wherein said first processing sequence further selects additional saidtemperature sensor data frames in between said initial and finaltemperature sensor data frames and determines associated timedifferentials between consecutive said selected additional temperaturesensor data frames, wherein said second processing sequence forcalculating a power density data further serially calculates powerdensity between each two of said selected temperature sensor data framesthen said second processing sequence sums all of the power density datafor each two consecutive temperature sensor data frame from said initialframe to said final frame to produce a final power density data.
 38. Amethod of manufacturing an electromagnetic field characterizationapparatus comprising: providing an electromagnetic source adapted toemit electromagnetic field; providing an electromagnetic absorptionmaterial adapted to receive said electromagnetic field; providing aplurality of temperature sensors adapted to orient on saidelectromagnetic absorption material and output a plurality oftemperature sensor data frames data, wherein said plurality oftemperature sensors comprise a plurality of temperature sensor pixelsand said plurality of temperature sensor data frame data each store atemperature data output from each said temperature sensor pixels;providing a plurality of processing sequences comprising: a firstprocessing sequence adapted to select and store an initial and finaltemperature sensor data frame from said plurality of temperature sensordata frames based on a first and second temperature parameter, saidfirst processing sequence further determines a differential temperaturedata associated with said initial and final temperature sensor dataframes; a second processing sequence for calculating a power densitydata associated with all or a portion of said plurality of temperaturesensors and said final temperature sensor data frame, said secondprocessing sequence determines said power density data based on a powerdensity per said pixel calculation comprising a peak power density valuebased on a plurality of calculation elements comprising a coefficient ofabsorption of the electromagnetic absorption material, a coefficient oftransmission of the electromagnetic absorption material, the finaltemperature of the electromagnetic absorption material, the initialtemperature of the electromagnetic absorption material, emissivity ofthe electromagnetic absorption material, Stefan-Boltzmann constant, aspecific heat of at least one heat sink, a volume of the at least oneheat sink, a density of the at least one heat sink, a contact areabetween the electromagnetic absorption material and the at least oneheat sink, a time differential between the initial and final temperaturesensor data frames, and degrees of freedom of atoms or molecules thatcomprise the electromagnetic absorption material and a plurality ofinputs to said power density per said pixel calculation including saiddifferential temperature data, wherein said calculation is modifiedbased on a particular said electromagnetic absorption material, whereinthe modified calculation components are coefficient of absorption of theelectromagnetic absorption material, a plurality of degrees of freedomdata for atoms or molecules associated with said electromagneticabsorption material associated with a blackbody radiation calculation,emissivity of blackbody radiation associated with said electromagneticabsorption material, specific heat capacity of the at least one heatsink placed in proximity to said electromagnetic absorption material,density of the at least one heat sink, volume of the at least one heatsink, and area of interface between the at least one heat sink and saidelectromagnetic absorption material; and a third processing sequence forproducing at least one graphical user interface, said at least onegraphical user interface comprises a power density image output producedbased on a plurality of ranges of power density which depicts said powerdensity data, said at least one graphical user interface also is adaptedto display one or more said power density data associated with at leastone of said plurality of temperature sensors.
 39. A method ofmanufacturing an electromagnetic field characterization apparatus as inclaim 38, further comprising providing a processing system adapted toprocess said plurality of processing sequences and produce a pluralityof outputs comprising said power density image output.
 40. A method ofmanufacturing an electromagnetic field characterization apparatus as inclaim 38, further comprising providing a temperature control mechanismwhich provides cooling to said electromagnetic absorption material. 41.A method of manufacturing an electromagnetic field characterizationapparatus as in claim 40, wherein said temperature control mechanism isa circulation fan.
 42. A method of manufacturing an electromagneticfield characterization apparatus as in claim 38, wherein saidelectromagnetic source is a radio frequency source coupled to anelectromagnetic field radiating structure.
 43. A method of manufacturingan electromagnetic field characterization apparatus as in claim 38,wherein said plurality of temperature sensors comprises one or moreinfrared image sensing apparatus.
 44. A method of manufacturing anelectromagnetic field characterization apparatus as in claim 38, whereinsaid first temperature parameter is a lowest temperature data value andsaid second temperature parameter is a highest temperature value.
 45. Amethod of manufacturing an electromagnetic field characterizationapparatus as in claim 38, further comprising a mechanism adapted to movesaid electromagnetic source or the electromagnetic absorption materialrelation to each other in order to manipulate either saidelectromagnetic field which is being measured or manipulate theelectromagnetic absorption material to move it through theelectromagnetic field which is being measured.
 46. A method forelectromagnetic field characterization comprising: providing anelectromagnetic source adapted to produce an electromagnetic field;providing an electromagnetic absorption material; providing an array oftemperature sensors; providing a processing system and input/outputsystem; positioning said array of temperature sensors and saidelectromagnetic source to orient on said electromagnetic absorptionmaterial based on a desired measurement of said electromagnetic fieldproduced by said electromagnetic source; acquiring a plurality oftemperature image data starting from a first point in time to finalpoint in time attained after a peak temperature of said electromagneticabsorption material is reached by at least one temperature sensors insaid array of temperature sensors or a predetermined point of time andsaving temperature per pixel data and time associated with eachtemperature per pixel data to a Temperature Data per Pixel (TDPP) dataarray; inputting data from said TDPP Array; selecting an initial framebased on a comparison of all frames in said TDPP array and identifyingone of said frames in said TDPP array having a coldest or lowest ambienttemperature or based on determining a time prior to activation of saidelectromagnetic source; selecting a final frame based on a comparison ofall frames in said TDPP array and identifying one of said frames in saidTDPP array having a highest temperature; determining power density dataassociated with each said pixel in said initial and final frames basedon a plurality of characteristics of said EM absorber includingabsorption coefficient, transmission coefficient, degrees of freedom,emissivity, Stefan-Boltzmann's Constant associated with saidelectromagnetic absorption material, number of sides of saidelectromagnetic absorption material being cooled, specific heat capacityof a coolant used to cool said electromagnetic absorption material,density of said coolant, volume of said coolant, area that said coolantwill be in contact with said electromagnetic absorption material, changein time between said initial and final frame capture, and an initial andfinal temperature data of the EM absorber.
 47. A method as in claim 46,further comprising providing a temperature control mechanism whichprovides cooling to said electromagnetic absorption material.
 48. Amethod as in claim 47 wherein said temperature control mechanism is acirculation fan.
 49. A method as in claim 46, wherein saidelectromagnetic source is a radio frequency source coupled to anelectromagnetic field radiating structure.
 50. A method as in claim 46,wherein said array of temperature sensors comprises an infrared imagesensing apparatus.
 51. A method as in claim 46, wherein said pluralityof temperature image data comprises a plurality of infrared image framecaptures.
 52. A method as in claim 46, wherein said first point in timeis a time prior to activation of said electromagnetic source.